Synthesis Of K1 Research Articles

Swift Adsorptive Removal of Congo Red from Aqueous Solution by K<SUB>1.33</SUB>Mn<SUB>8</SUB>O<SUB>16</SUB> Nanowires

A swift and efficient approach to converting organic dye effluents into fresh water could be of substantial benefit. In this study, we presented facile hydrothermal synthesis of K1.33Mn8O16 nanowires in ammonium fluoride (NH4F) aqueous solution. The crystallization process of K1.33Mn8O16 nanowires was investigated. The as-obtained K1.33Mn8O16 nanowires were used for swift adsorptive removal of Congo red from aqueous solution without adjusting pH value at room temperature. Adsorption kinetic experimental data are well described by pseudo-second-order rate kinetic model, and the adsorption isotherm fits Langmuir isotherm model. The present investigation provides an efficient approach to designing and fabricating manganese-based nanomaterials for environmental remediation.

Density-dependent modulation of synthesis of keratins 1 and 10 in the human keratinocyte line HACAT and in ras-transfected tumorigenic clones

Abstract The spontaneous human keratinocyte line HaCaT and C-Ha-ras oncogene-transfected cell clones are capable of expressing an unusually broad spectrum of keratins, not observed so far in epithelial cells. This expression is, however, strongly modulated by environmental conditions, including cell density. Both cells of the nontumorigenic HaCaT line and the tumorigenic HaCaT- ras clones, I-7 and II-3 (giving rise to benign and malignant tumors, respectively), constitutively expressed the keratins K5, K6, K14, K16 and K17, which are also common in clutures of normal keratinocytes. In addition keratins K7, K8, K18 and K19, generally associated with simple epithelia, were synthesized (to a most pronounced extent in spase cultures), while keratins K4, K13 and K15 appeared at confluence, presumably with the onset of stratification. Moreover, in both HaCaT and HaCaT- ras clones the epidermal “suprabasal” keratins, K1 and K10, were expressed in conventional submerged cultures (at normal vitamin A levels), markedly rising with cell density, but not strictly correlated with the degree of stratification. This property was maintained in HaCaT cells up to the highest passages. According to immunofluorescence, this was due to increasing numbers of strongly stained cells, and not due to a gradual increase in all cells. Most strikingly, there was a significant delay in the appearance of K10 compared to K1, and this dissociation of expression was most evident in dispase-detached cell sheets (submerged cultures) and organotypic cultures of the ras clones (grown at the air-liquid interface). While on frozen sections bright staining for K1 was seen in some basal and virtually all suprabasal cell layers, K10 was largely restricted to the uppermost layers. Thus, obviously synthesis of K1 and K10 can be regulated independently, although generally in this given sequence. The apparent compatibility of K1 synthesis with proliferation and particularly the extended delay of K10 expression (as a postmitotic event) might be causally related to altered growth control and as such imply the significance of this disturbance. Finally, the highly preserved epidermal characteristics, in terms of expression of keratins (and other differentiation markers [5]) and their regulation, makes these cell lines excellent candidates for studying external modulators of differentiation and also underlying molecular mechanisms.

The K1 capsular polysaccharide of Escherichia coli.

Epidemiologic, immunologic, and genetic evidence indicate that the K1 capsular polysaccharide confers invasiveness to Escherichia coli. The capsule, an alpha-2----8-linked homopolymer of sialic acid (NeuNAc), provides the bacterium with a physical antiphagocytic barrier. Structural similarities between K1 and human tissue components suggest that immune tolerance may also be a factor in pathogenesis of K1 disease. The molecular and genetic events involved in the synthesis and export of the K1 polysaccharide were examined. The cloned K1 genes encode at least 12 proteins involved in capsule biosynthesis. These genes appear to be coordinately regulated and functionally clustered. One cluster is associated with the synthesis and activation of NeuNAc and includes the gene encoding CMP-NeuNAc synthetase. This enzyme catalyzes the activation of NeuNAc to CMP-NeuNAc. A second region, encoding five proteins, is associated with translocation of polysaccharide to the bacterial surface. The K1 polysaccharide is a poor immunogen in humans, and an understanding of the key reactions involved in K1 synthesis may help in providing an alternative to anticapsular immunity.